1. Field of the Invention
The present invention relates to an inlet guide vane installed at a suction port where a fluid is drawn in by rotation of an impeller for adjusting the suction amount and flow direction of a fluid, a compressor that is provided with it, and a refrigerator that is provided with this compressor.
Priority is claimed on Japanese Patent Application No. 2008-27075, filed Feb. 6, 2008, the content of which is incorporated herein by reference.
2. Description of Related Art
As a refrigerator that cools or refrigerates a cooling object such as water, there is known a refrigerator and the like that is equipped with a compressor that compresses and discharges a refrigerant (fluid) with an impeller. In a compressor, when the compression ratio becomes large, the discharge temperature of the compressor becomes high, causing a drop in volume efficiency. For this reason, there is also a compressor constituted so as to perform compression of the refrigerant over a plurality of stages. For example, a turbo compressor disclosed in Japanese Unexamined Patent Application, First Publication No. 2007-177695 has two compression stages that are provided with an impeller and a diffuser, and sequentially compresses the refrigerant with these compression stages.
In such a turbo compressor, a suction port for drawing a refrigerant inside by rotation of an impeller of a first compression stage is established in such a turbo compressor is provided. A plurality of inlet guide vanes for adjusting the suction amount and the flow direction of the refrigerant are arranged in parallel in the circumferential direction in the suction port of this turbo compressor.
An inlet guide vane 100 shown for example in FIG. 8 has a shaft 101 and plate-shaped vane body 102 in an approximate fan shape viewed from the side that is joined in a state of a mutual axis line O1 being disposed coaxially on this shaft 101 (for example, refer to Japanese Patent Publication No. 2626253 (Japanese Unexamined Patent Application, First Publication No. H04-224299)). The shaft 101 has a shaft main body portion 107 and a stage portion 108. A bearing sleeve 106 of a drive mechanism 105 is fixed to a housing 104 which forms a suction port 103. The shaft main body portion 107 has a cylindrical shape, and is inserted in this bearing sleeve 106 to be supported in a manner capable of turning about the axis line O1. The stage portion 108 is provided at the distal end side in the axis line O1 direction to join with the vane main body 102, and has an outer diameter (width B1 in the direction perpendicular to the axis line O1) approximately equal to the outer diameter d1 of the bearing sleeve 106. This inlet guide vane 100 is supported in a state of the shaft main body portion 107 being inserted in the bearing sleeve 106. The inlet guide vane 100 is installed in the state of the vane main body 102 projected to the inside in the radial direction from the inner periphery surface 103a of the suction port 103 to the center portion. At this time, the inlet guide vane 100 is installed so as to receive the stage portion 108 with an end portion 106a of the bearing sleeve 106.
The inlet guide vane 100 installed in this way adjusts the suction amount and the flow direction of the refrigerant that is drawn in by turning about the axis line O1 with the drive mechanism 105 according to the angle of attack (turning angle) of each inlet guide vane 100.
However, in the above-mentioned conventional inlet guide vane 100, since the stage portion 108 of the shaft 101 has an outer diameter (width B1) approximately equal to the outer diameter d1 of the bearing sleeve 106 so as to be receivable by the bearing sleeve 106, the stage portion 108 is small. For this reason, when the inlet guide vane 100 is pressed by the flow of the refrigerant, and the stage portion 108 makes partial contact with the bearing sleeve 106 (while adjusting the flow amount and flow direction of the refrigerant), a locally large thrust force N acts on the end portion 106a of the bearing sleeve 106. Thereby, local eccentric wear occurs at the bearing sleeve 106, leading the problem of the service life of the bearing sleeve 106 being shortened.